Add an handler to update the total number of records after a write action.

Have this information up to date is required by the paging plugin.

static/plugin_dbui/src/appjsonstore.js

@@ -77,6 +77,27 @@ App.data.DirectStore = Ext.extend(Ext.data.DirectStore, {
         
         // instantiate the store
         App.data.DirectStore.superclass.constructor.call(this, cfg);
+
+        // update the total number of records        
+        this.on('write', this.onWrite);
+    },
+    
+    /**
+     * Handler to update the total number of records after a write action
+     * @param {Object} store
+     * @param {Object} action
+     */
+    onWrite: function (store, action) {
+        
+        switch (action) {
+            case 'create':
+                store.totalLength += 1;
+                break;
+        
+            case 'destroy':
+                store.totalLength -= 1;
+                break;
+        }
     }
 });